no more assignment expressions (they don't fit in Lua...)

lopcodes.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lopcodes.h,v 1.30 1999/03/04 21:15:50 roberto Exp roberto $
+** $Id: lopcodes.h,v 1.31 1999/03/05 21:16:07 roberto Exp roberto $
 ** Opcodes for Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -26,7 +26,6 @@ TAILCALL,/*	b c	v_c...v_1 f	(return)	f(v1,...,v_c)	*/
 
 PUSHNIL,/*	b	-		nil_0...nil_b			*/
 POP,/*		b	a_b...a_1	-				*/
-POPDUP,/*	b	v a_b...a_1	v				*/
 
 PUSHNUMBERW,/*	w	-		(float)w			*/
 PUSHNUMBER,/*	b	-		(float)b			*/
@@ -56,18 +55,13 @@ CREATEARRAYW,/*	w	-		newarray(size = w)		*/
 CREATEARRAY,/*	b	-		newarray(size = b)		*/
 
 SETLOCAL,/*	b	x		-		LOC[b]=x	*/
-SETLOCALDUP,/*	b	x		x		LOC[b]=x	*/
 
 SETGLOBALW,/*	w	x		-		VAR[CNST[w]]=x	*/
 SETGLOBAL,/*	b	x		-		VAR[CNST[b]]=x	*/
-SETGLOBALDUPW,/*w	x		x		VAR[CNST[w]]=x	*/
-SETGLOBALDUP,/*	b	x		x		VAR[CNST[b]]=x	*/
 
 SETTABLEPOP,/*	-	v i t		-		t[i]=v		*/
-SETTABLEPOPDUP,/* -	v i t		v		t[i]=v		*/
 
 SETTABLE,/*	b	v a_b...a_1 i t	 a_b...a_1 i t	  t[i]=v	*/
-SETTABLEDUP,/*	b	v a_b...a_1 i t	 v a_b...a_1 i t  t[i]=v	*/
 
 SETLISTW,/*	w c	v_c...v_1 t	t		t[i+w*FPF]=v_i	*/
 SETLIST,/*	b c	v_c...v_1 t	t		t[i+b*FPF]=v_i	*/

lparser.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 1.26 1999/03/04 21:17:26 roberto Exp roberto $
+** $Id: lparser.c,v 1.27 1999/03/05 21:16:07 roberto Exp roberto $
 ** LL(1) Parser and code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -99,7 +99,7 @@ typedef struct FuncState {
 /*
 ** prototypes for non-terminal functions
 */
-static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes);
+static int assignment (LexState *ls, vardesc *v, int nvars);
 static int cond (LexState *ls);
 static int funcname (LexState *ls, vardesc *v);
 static int funcparams (LexState *ls, int slf);
@@ -114,7 +114,6 @@ static void chunk (LexState *ls);
 static void constructor (LexState *ls);
 static void decinit (LexState *ls, listdesc *d);
 static void exp0 (LexState *ls, vardesc *v);
-static void Gexp (LexState *ls, vardesc *v);
 static void exp1 (LexState *ls);
 static void exp2 (LexState *ls, vardesc *v);
 static void explist (LexState *ls, listdesc *e);
@@ -467,22 +466,16 @@ static void lua_pushvar (LexState *ls, vardesc *var) {
 }
 
 
-/* to be used by "storevar" and assignment */
-static OpCode set_pop[] = {SETLOCAL, SETGLOBAL, SETTABLEPOP, SETTABLE};
-static OpCode set_dup[] = {SETLOCALDUP, SETGLOBALDUP, SETTABLEPOPDUP,
-                           SETTABLEDUP};
-
-
-static void storevar (LexState *ls, vardesc *var, OpCode *codes) {
+static void storevar (LexState *ls, vardesc *var) {
   switch (var->k) {
     case VLOCAL:
-      code_oparg(ls, codes[0], var->info, -1);
+      code_oparg(ls, SETLOCAL, var->info, -1);
       break;
     case VGLOBAL:
-      code_oparg(ls, codes[1], var->info, -1);
+      code_oparg(ls, SETGLOBAL, var->info, -1);
       break;
     case VINDEXED:
-      code_opcode(ls, codes[2], -3);
+      code_opcode(ls, SETTABLEPOP, -3);
       break;
     default:
       LUA_INTERNALERROR("invalid var kind to store");
@@ -739,7 +732,7 @@ static int stat (LexState *ls) {
       next(ls);
       needself = funcname(ls, &v);
       body(ls, needself, line);
-      storevar(ls, &v, set_pop);
+      storevar(ls, &v);
       return 1;
     }
 
@@ -765,7 +758,7 @@ static int stat (LexState *ls) {
         close_exp(ls, v.info, 0);
       }
       else {  /* stat -> ['%'] NAME assignment */
-        int left = assignment(ls, &v, 1, set_pop);
+        int left = assignment(ls, &v, 1);
         adjuststack(ls, left);  /* remove eventual 'garbage' left on stack */
       }
       return 1;
@@ -948,19 +941,6 @@ static void exp0 (LexState *ls, vardesc *v) {
 }
 
 
-static void Gexp (LexState *ls, vardesc *v) {
-  /* Gexp -> exp0 | assignment */
-  exp0(ls, v);
-  if (v->k != VEXP && (ls->token == '=' || ls->token == ',')) {
-    int left = assignment(ls, v, 1, set_dup);
-    deltastack(ls, 1);  /* DUP operations push an extra value */
-    if (left > 0)
-      code_oparg(ls, POPDUP, left, -left);
-    v->k = VEXP; v->info = 0;  /* this expression is closed now */
-  }
-}
-
-
 static void push (LexState *ls, stack_op *s, int op) {
   if (s->top >= MAXOPS)
     luaX_error(ls, "expression too complex");
@@ -1015,9 +995,9 @@ static void simpleexp (LexState *ls, vardesc *v, stack_op *s) {
       ifpart(ls, 1, ls->linenumber);
       break;
 
-    case '(':  /* simpleexp -> '(' Gexp ')' */
+    case '(':  /* simpleexp -> '(' exp0 ')' */
       next(ls);
-      Gexp(ls, v);
+      exp0(ls, v);
       check(ls, ')');
       return;
 
@@ -1239,7 +1219,7 @@ static void decinit (LexState *ls, listdesc *d) {
 }
 
 
-static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes) {
+static int assignment (LexState *ls, vardesc *v, int nvars) {
   int left = 0;
   unloaddot(ls, v);
   if (ls->token == ',') {  /* assignment -> ',' NAME assignment */
@@ -1248,7 +1228,7 @@ static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes) {
     var_or_func(ls, &nv);
     if (nv.k == VEXP)
       luaX_error(ls, "syntax error");
-    left = assignment(ls, &nv, nvars+1, set_pop);
+    left = assignment(ls, &nv, nvars+1);
   }
   else {  /* assignment -> '=' explist1 */
     listdesc d;
@@ -1258,15 +1238,16 @@ static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes) {
   }
   if (v->k != VINDEXED || left+(nvars-1) == 0) {
     /* global/local var or indexed var without values in between */
-    storevar(ls, v, codes);
+    storevar(ls, v);
   }
   else {  /* indexed var with values in between*/
-    code_oparg(ls, codes[3], left+(nvars-1), -1);
-    left += 2;  /* table/index are not popped, because they aren't on top */
+    code_oparg(ls, SETTABLE, left+(nvars-1), -1);
+    left += 2;  /* table&index are not popped, because they aren't on top */
   }
   return left;
 }
 
+
 static void constructor (LexState *ls) {
   /* constructor -> '{' part [';' part] '}' */
   int line = ls->linenumber;

lvm.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lvm.c,v 1.52 1999/03/04 21:15:50 roberto Exp roberto $
+** $Id: lvm.c,v 1.53 1999/03/05 21:16:07 roberto Exp roberto $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -356,11 +356,6 @@ StkId luaV_execute (Closure *cl, TProtoFunc *tf, StkId base) {
         S->top -= aux;
         break;
 
-      case POPDUP: aux = *pc++;
-        *(S->top-aux-1) = *(S->top-1);
-        S->top -= aux;
-        break;
-
       case PUSHNUMBERW: aux += highbyte(*pc++);
       case PUSHNUMBER:  aux += *pc++;
         ttype(S->top) = LUA_T_NUMBER;
@@ -424,45 +419,20 @@ StkId luaV_execute (Closure *cl, TProtoFunc *tf, StkId base) {
         *((S->stack+base) + aux) = *(--S->top);
         break;
 
-      case SETLOCALDUP: aux = *pc++;
-        *((S->stack+base) + aux) = *(S->top-1);
-        break;
-
       case SETGLOBALW: aux += highbyte(*pc++);
       case SETGLOBAL:  aux += *pc++;
         luaV_setglobal(tsvalue(&consts[aux]));
         break;
 
-      case SETGLOBALDUPW: aux += highbyte(*pc++);
-      case SETGLOBALDUP:  aux += *pc++;
-        *S->top = *(S->top-1);
-        S->top++;
-        luaV_setglobal(tsvalue(&consts[aux]));
-        break;
-
       case SETTABLEPOP:
         luaV_settable(S->top-3);
         S->top -= 2;  /* pop table and index */
         break;
 
-      case SETTABLEPOPDUP: {
-        TObject temp = *(S->top-1);
-        luaV_settable(S->top-3);
-        S->top--;  /* pop index (temp goes into "table" position) */
-        *(S->top-1) = temp;
-        break;
-      }
-
       case SETTABLE:
         luaV_settable(S->top-3-(*pc++));
         break;
 
-      case SETTABLEDUP:
-        *S->top = *(S->top-1);
-        S->top++;
-        luaV_settable(S->top-(3+1)-(*pc++));
-        break;
-
       case SETLISTW: aux += highbyte(*pc++);
       case SETLIST:  aux += *pc++; {
         int n = *(pc++);

manual.tex

@@ -1,4 +1,4 @@
-% $Id: manual.tex,v 1.24 1999/02/25 19:13:56 roberto Exp roberto $
+% $Id: manual.tex,v 1.25 1999/03/04 21:23:39 roberto Exp roberto $
 
 \documentclass[11pt]{article}
 \usepackage{fullpage,bnf}
@@ -41,7 +41,7 @@ Waldemar Celes
 \tecgraf\ --- Computer Science Department --- PUC-Rio
 }
 
-%\date{\small \verb$Date: 1999/02/25 19:13:56 $}
+%\date{\small \verb$Date: 1999/03/04 21:23:39 $}
 
 \maketitle
 
@@ -697,14 +697,6 @@ according to its condition.
 Its final value is the value of the chosen expression.
 An absent else-part is equivalent to \verb|else nil|.
 
-\subsubsection{Assignment Expressions}
-\begin{Produc}
-\produc{exp}{\ter{(} varlist1 \ter{=} explist1 \ter{)}}
-\end{Produc}%
-An \Index{assignment expression} executes a multiple assignment,
-and results in the final value of its first right hand expression
-(that is, the value assigned to the first variable in the variable list).
-
 \subsubsection{Table Constructors} \label{tableconstructor}
 Table \Index{constructors} are expressions that create tables;
 every time a constructor is evaluated, a new table is created.